A) Field of the Invention
This invention relates to a voice synthesizing apparatus, and more in detail, relates to a voice synthesizing apparatus that can synthesize a singing voice with vibrato.
B) Description of the Related Art
Vibrato that is one of singing techniques is a technique that gives vibration to amplitude and a pitch in cycle to a singing voice Especially, when a long musical note is used, a variation of a voice tends to be poor, and the song tends to be monotonous unless vibrato is added, therefore, the vibrato is used for giving an expression to this.
The vibrato is a high-grade singing technique, and it is difficult to sing with the beautiful vibrato. For this reason, a device as a karaoke device that adds vibrato automatically for a song that is sung by a singer who is not good at singing very much is suggested.
For example, in Japanese Patent Laid-Open No. 9-044158, as a vibrato adding technique, vibrato is added by generating a tone changing signal according to a condition such as a pitch, a volume and the same tone duration of an input singing voice signal, and tone-changing of the pitch and the amplitude of the input singing voice signal by this tone changing signal.
The vibrato adding technique described above is generally used also in a singing voice synthesis.
However, in the technique described above, because the tone changing signal is generated based on a synthesizing signal such as a sine wave and a triangle wave generated by a low frequency oscillator (LFO), a delicate pitch and a vibration of amplitude of vibrato sung by an actual singer cannot be reproduced, and also a natural change of the tone cannot be added with vibrato.
Also, in the prior art, although a wave sampled from a real vibrato wave is used instead of the sine wave, it is difficult to reproduce the natural pitch, amplitude and tone vibrations from one wave to all waves.